Forgive us our trespasses
by Kato Molotov
Summary: [Early S6 AU – no D.C. arc. Summer Kink Meme '14] Castle does what he has to protecting his family and prepares to bear the consequences. COMPLETE... for now.
1. The Pattern Never Alters Until

**Prompt**: Castle kills Tyson (premeditated) and confesses to Beckett. Instead of being appalled and turning him in, she's turned on by it.

* * *

Not many people know that it takes an average of three minutes from application of force to death from strangling. Unconsciousness happens quickly – if the victim is lucky – but death is slow.

Richard Castle knows.

* * *

It's happy accident. A once-in-a-lifetime opportunity. Eight million people in this city, and who does he see out and about with all the other monsters on Halloween, not even bothering to wear a mask? Not that he needs it – Castle's been writing and hanging around murder long enough to know that the worst monsters are only human.

Right out there in broad daylight, a sick fantasy that's lived in the dark recesses of his mind for years at last has the chance to bear fruition, to become.

He was on his way home after popping out for some last minute party supplies. The guests will be arriving in two hours, costumes mandatory. He made sure Beckett understood the _mandatory_ part, and oh he can't _wait_ to peel whatever costume she's come up with off her (damn woman won't tell him, but Ryan and Esposito know and they said he'll like it, which just makes waiting that much more unbearable) and celebrate their first Halloween together. The night they'll announce their engagement to their friends and the public at large.

His mind is made up.

Castle hopes he'll be celebrating something else entirely tonight too, if only in his own mind. The freedom from the fear, the chance to live no longer haunted by the every shadow on the wall or footfall in the night.

Martha has done a bang-up job on his makeup. His ruggedly handsome features have been temporarily morphed into something well and truly grotesque, reprising his starring role as zombie.

The soul-dead serial killer walks right up next to him, stands on line at the news station and buys a paper, even makes almost-normal conversation with the guy manning the stand as Castle busies himself with his phone six feet away. Tyson saunters off none-the-wiser, and Castle almost can't believe his good luck.

(_Predictable, Jerry; so predictable. I'm almost embarrassed for you. People don't buy papers far from their own homes, now do they? That was your mistake, Jerry. That will be your undoing. Buying a paper, trying to pass yourself off as a human being.)_

Adrenalin rushes through the author, his hands clenching and unclenching reflexively. Heart racing even at the casual pace he keeps behind his mark, the anticipation of the kill unexpectedly thrilling. His shoulders roll ferally as he stalks - the picture, to any onlooker, of barely-controlled power, holding himself back on a tight leash from attacking before the moment is right.

He's written this scene a thousand times in his head. The USB he keeps hidden in his desk once housed the Beckett file, but with Senator Bracken's fortuitous run-in with a car bomb, he's replaced it with a dozen Word files. Stories he'll never publish about a certain reporter exacting some kind of gruesome revenge on a serial killer whose personal mission is to destroy the life Rook's trying to build with Nikki and their family.

Until now, he's always told himself it was just catharsis, a creative outlet for the frustrations of having no leads on Tyson. Indeed, no contact at all since the night at the bridge. Beckett says he's paranoid, when he occasionally has Ryan sweep the loft for bugs or cameras, or rants to her about how it could have survived and is probably watching them, waiting for them. Deep down, Castle thinks she knows too. She just doesn't want to admit it. Besides that, she doesn't have this primal _need_ to see Tyson's lifeless, miserable shell and know it's finally over. Not like he does. It's his quest, his dragon, not hers.

It became personal when Tyson hurt Ryan and threatened him, taunted him, dared to compare Rick to himself. It became a mission when it used Ryan's gun to try to set up the younger detective, the brotherly affection in him roaring at the manipulative invasion. It became an obsession when it dared touch _Beckett_, dared to try to use her against him. No one threatened Beckett. No one _watched them, _invaded their sanctuary, and got away with it. No one dared to taint the memory of something as beautiful and perfect as their moments alone.

Looking back on it now, that was when he knew. The moment he found out Tyson had been in his home, watched him with his family. He _knew_. It's a cliché of the Chosen One heroic tale genre: neither can live with the other survives. Something like that.

There was a time when he thought Kate Beckett was possibly unstable, for how much her mother's case drove and consumed her, how frighteningly obsessed she was by it. After Tyson, he understands. He knows there'll be no peace for him or Beckett or any of their family (blood or otherwise) or safety for anyone else while Tyson lives.

He knew he'd ultimately end Tyson. He just always figured it would be a case of self-defense, not an execution.

Jail is not enough. He realized that some time ago. Merely catching Tyson would do little good. The thing would act through someone else, or escape, no matter what failsafes the prison system thinks they can place on it.

Now, he knows for sure. All that writing and thinking and – dare he say it – fantasizing, was no mere catharsis. It was a rehearsal. A solemn oath, a manifesto.

He has the file where Rook kills famed serial killer Terry Bryson with a shot to the back of the head after finding Bryson lurking in the apartment, feet away from a sleeping Nikki. He has the file where Bryson confronts Rook in the subway, a struggle initiated by the serial killer ending with Rook pushing his nemesis in front of a speeding train and watching with satisfaction as the wheels saw the miserable body in half as dozens of people look on, and isn't that just a little exhibitionist?

And then he has his favorite file. It's the one he secretly goes back and reads when he's restless and worried about Tyson as Kate sleeps peacefully in his bed just feet away. The one where Rook turns the tables on Bryson and stalks the stalker, follows the beast back to its lair, and puts it down like the piteous animal it is. He likes that one best. Castle finds something so very poetic about letting Rook kill Bryson in the beast's own inner sanctum, after having his and Nikki's privacy so abhorrently invaded.

Life, imitating art? Perhaps. It's almost eerie how well this fits with his stories, but truth, as they say, is stranger.

Three blocks over from the news stand, Tyson gives a furtive glance around, as if to check for anything unusual. But it's Halloween, and everything is unusual. Dark, rodent-like eyes dart about nervously, scanning the street, as if the being has an unnatural sense to know when it's being followed. Castle hangs back in the middle of a pack of werewolves like he belongs there, like it's all part of the festivities.

Following his target over the threshold, he watches the thing pass through the lobby (no doorman, excellent) and into the far-left elevator, the "4" lighting up above it as the doors slide closed. Castle's mind whizzes: left side of the building, fourth floor. Can't be more than six apartments in that wing. It's figuring out which one is Tyson's that's the challenge.

He rides the elevator up with Buffy and Spike, too preoccupied making out to notice him, and the guy from that zombie cable drama who jokingly points a toy crossbow at him. Castle smirks in return. An elevator full of monster hunters ascends, cheerful bubblegum pop playing over the polite silence of the cramped space. Buffy and Spike depart on 3, and the zombie hunter is waiting for 6. Castle departs with his best zombie growl that seems to delight the crossbow-wielding partygoer.

Seeing no one in the plain but well-lit hallway, Castle decides to use the holiday to his advantage and just go with the brute force approach. Try doors until he gets the right one.

Steadying himself – easy, Rick, you only get one chance at this – he knocks on the first door.

Can I help you? a young woman says through the cracked door, chain still latched.

Oh, he feigns surprise, this isn't the costume party? My mistake.

The woman sighs with relief, opening the door fully as she chats happily and says that the Pierce's party is at 6B, not 4B. She smiles and flirts, simpers, I like your costume; maybe I'll see you there later, as she closes the door.

He's just thinking about how he can use this information when another door creaks open, two down.

Tyson doesn't connect it immediately and it buys Castle precious time, his feet carrying him swiftly. The smaller being seems to realize what's going on as Castle meets its beady eyes, already looming over it as Tyson tries to slam the door, reach for a weapon, anything. Tyson is no sucker, but Castle is much, much bigger and stronger.

The rage, hatred, fear, and pure desire for revenge give him an even greater strength advantage, the extra energy fuelling him and making his brain and vision swim deliriously, blood rushing in his ears, heart in his throat, a deranged high coursing through his veins. On their own accord, Castle's hands wrap around his nemesis' neck, steering it back into the apartment without a sound.

Tyson fights like a trapped animal, thrashing, landing punch after punch to Castle's chest, but it's of little use. Castle's had worse, and besides that, he's even stronger than he looks. Though he prefers not to throw his weight around with suspects, allows the real cops to do their jobs without his potentially legally-complicated involvement in arrests whenever possible, he holds his own when there's need of it. The adrenalin coursing through him means it won't hurt until much later. A knee pressing into Tyson's chest, immobilizing it easily, Castle adjusts his large hands around the neck of the hideous creature and _chokes_.

There's something incalculably satisfying about it, as the seconds tick by, there on the ground in the entryway to Tyson's abode. He plays with his quarry like a young coyote with a hare, thrill zinging through his body, making his blood sing as he edges his prey close to unconsciousness, then eases up just enough to revive awareness. He idly wonders if this is what being god feels like, as he makes absolutely certain this forsaken thing knows fear in death as it never knew in life.

Tyson's punches grow weaker, then stop falling altogether. The face turns a fascinating white, then red, then bluish-grey as inky eyes bulge and loll crazily in their sockets, the only noise in the room the occasional wheezing gasp, the rattle of death.

Castle's only watched a person die up close once before. Both times, he hovered overhead, watching the whole thing. It's a strange symmetry, watching Beckett die versus watching Tyson die. The person he loves most versus the only thing Castle can honestly say he's ever _hated._ The first time, every second was a desperate plea for time, for another chance, for a miracle, whatever the price. This time, he's making certain there will be no resurrection, no miracle for the damned.

"How close… to death… do you want to get, Jerry?" he taunts, his breath heavy with exertion and unhinged ecstasy.

Watching the light die in the madman's black, abyssal eyes as his thumbs crush Tyson's windpipe and cut off the last vital bit of oxygen to his brain, Castle feels a rush of satisfaction, excitement, relief, vindication. He's free. They're free. He and Beckett can move on with their lives, can be a family, can have a family, and live free from having to look over their shoulders for Bracken or Tyson. He holds for a minute longer, making absolutely certain that the walking nightmare is gone.

Rising at last, he takes a deep, steadying breath and begins robotically cleaning up what little of a scene there is, his many years with the cops and knowledge of CSU and M.E. procedure finally coming to real-world use.

It's over. It's gone.

* * *

What took you so long? Frankensito greets as he walks in the door of the loft, seeing it transformed by his patchwork family into Halloween central.

Place was an absolute zoo, as you can imagine, Castle is ready with the lie and spits it out easily, having anticipated the questioning. Had to wait on line forever, then I almost got home and realized I forgot to buy dry ice, so I had to go back.

Frankensito shrugs, satisfied with his answer, and Ryan – or the Artist Formerly Known as Ryan, if his costume is anything to go by - bounds up to talk to him about cocktails from behind the kitchen counter where he and Jenny/Madonna are preparing hors d'oeuvres.

An hour later the party is in full swing, the loft filled with people. Kate's hanging close to him in her lovely Indiana Jones costume, sinfully ill-tailored for fighting Nazis or running from booby-trapped temples. She even has a bullwhip.

Castle's not able to enjoy any of it. Panic claws at his chest, guilt flooding him, dragging him down and filling his mouth and nose and lungs.

Not about killing Tyson – that _thing_ needed to be done away with – but about lying to Beckett. About what it'll do to her and Alexis and his mother and Ryan and Esposito if this comes back to him, if he has to go away. About the pain of a trial, about some D.A. or his attorney making Beckett testify for or against him. About the wedding they'll never have, the family they'll never have.

Small-talk with Gargoyle Markway fails to hold his attention.

Heard you brought back Derrick Storm?

Yes, for now.

Good, good.

How's your wife?

Good, good. Care to stake some of those royalties on a game of golf with Bob next weekend? We like you. You make us look like we know what we're doing.

I'll see if I can clear a spot in my schedule.

Castle escapes as quickly he possibly can without attracting attention, makes for his bathroom, bile rising in his throat as he drops to his knees with a clash he feels in his bruised ribs. His insides become black and slimy writhing things of the murky depths as he bows his head, feels the burn up his esophagus, and vomits.

Dizzy, he presses his face against the cool of the wall, sagging back against it and leaving black and green streaks of makeup against the pale subway tile where his cheek rested.

"Castle?" Beckett calls.

Shit.

"'m fine," he groans weakly, but upon seeing her stand in the doorway, his stomach flips all over again.

Humiliation mixes with fear and guilt, her seeing him like this. How could he be so rash, so stupid? A few minutes of satisfaction, even if they lead to the safety from Tyson that's now theirs, they're not worth what he's just thrown away. Her love, her trust. The security of Alexis and his mother. The only real friendships he has – real smart move, Rick. Kill someone when your best friends are cops and are likely to catch the case once the body's found.

They won't roll on him, he knows that much. But they should. Dear god, they should; they shouldn't have to cover for him, lie for him. They already carry Montgomery's sins in their throats. Somehow, the fallen Captain's secrets haven't been exposed even as the late Senator's secrets continue to come out, a posthumous parade of corruption and deceit. They shouldn't have another mouthful of lies to swallow, and he vows to spare at least Ryan and Esposito, if he can. They don't need to suffer for him.

"Castle!" she snaps fearfully, he knows he must be drifting in and out. Her voice sounds hollow and far away.

"Kate…" he mumbles, still swimming, still underwater. "Oh, Kate, I need to tell you something."

Kneeling down next to him and rubbing the back of his neck with a tenderness that makes him sick, she waits patiently. "Tell me, babe."

"Not here. Can you…" he thinks fast, trying to come up with a plan, "can you make my excuses to Mother and ask Jenny and Ryan to take over hosting? We need to go to your place."

To her credit, Kate doesn't bring up their definitely-not-happening-tonight announcement, sensing the gravity of this information.

"Okay," she takes a deep breath, "okay. Can you stand up?"

Castle hauls himself by the counter and sways a bit, but he's sturdy enough.

"Yeah, I'll be okay. I'm going to get some water and clean up."

Gargling and brushing his teeth thoroughly, Castle scrubs the makeup from his face, pulls and combs his hair back into something like normal, and after drinking some water, he feels a little calmer.

They manage to escape the party with little more than a concerned feel-better-bro from Espo and a reassurance from Martha.

I'll have the guests out at a respectable hour: two, three in the morning, tops, she says airily, her Harley chick bleach-blonde wig flipping as she turns back to the party and they slam the door behind them in their desperation to get out. See you in the morning, darlings!

The subway ride is silent.

They kick off their shoes at her door and she takes his cold and clammy hand in hers, sliding his shambled coat off his shoulders and dropping her hat on top of it in the foyer.

"What's wrong, Castle?"

Best to just get it over with. Spit it out. The sooner she hears, the sooner she arrests him, the better.

He says it flatly, emotion sapped from him as he gives everything he has up, lost on a momentary whim, the final victim of his own dark impulses and ill-conceived protective desires.

"I killed Tyson."

* * *

**Note**: Will be a two (maybe three) parter. Since this is Kink Meme, porn is a promise.

This is wayyyyy out of my comfort zone, thematically and stylistically, so I'd really love to hear what you think. As always, comments, questions, concerns, complaints and constructive criticisms are very much appreciated and responded to.


	2. The Rat Dies

The confession sets over them with a hush of desperation and hangs in the air like a miasma. He stops breathing, waiting, waiting for her answer. For an accusation, for a judge and jury in her word, for a sentence that never comes.

"Tell me," Kate states in an even, tone, turning from him only to light a fire in her dim living room. She beckons him over to sit by her side on the plush rug, leaned against her couch. Not afraid of the man who just confessed to murder, she blinks up as he looms over her, her trust in him implicit even with his revelation.

Castle takes a deep, miry breath and drops to the floor beside her. She can't help but notice the way his joints creak a little more than they did this morning. The levee lets loose. A glut of guilt and justification, the rickety dam of his emotions breaking and leveling everything in its path.

She knows he can lie to just about anyone, and he can lie well. But he's not lying. He doesn't lie to her. That thought alone sends the firey quiver of damnation through her conscience.

"He walked right past me on the street and bought a paper," he begins, "I don't even remember the walk there. I just… locked on and followed him."

Kate nods, slips her warm little hand into his. He jerks as if disgusted. The stab of fear she's felt for so many months sears through her, every time a single action is inconsistent with blissful ignorance on his part.

She listens as he methodically recounts the details, his expression neutral and his features half obscured in the low light of her apartment. His voice is remote, as if he were merely relaying someone else's account or unenthusiastically reading a page from one of his books for a crowd after being pestered into it. He tells her. From the moment he spotted Tyson to when he swung by the party store a second time. How used his friendship with the owner to jump the long lines and get the dry ice. Thought ahead to give himself a credible timeframe if questioned at home.

"I got lucky," he sighs, the insanity of the whole ordeal finally catching up with him. "Lucky to be in the right place at the right time. Lucky there were no witnesses. Lucky it's Halloween. Lucky there was no knife or gun on Tyson."

Decision time. Which side are you on, Kate, which side are you on?

It's no decision, in the end. It never has been, not for her, not with him. Her duty is to the victims, not to the monsters.

"Yes," Kate says. "You got lucky you weren't hurt too badly."

Castle recoils as if waiting to be kicked.

"Did you take anything from the scene?"

Silence. This was not what he expected. Kate wonders what had to have happened to him, that he's forever waiting for the next blow to fall, the other shoe to drop, to wake up from the dream and find it all gone.

(She wonders what that says about them, that he still expects her to choose her job.)

"His laptop and a stack of digital memory cards and USBs on his desk. Place was Spartan, he must be new there or he has another hideout. It doesn't add up. Unless he went all digital, he's got a wall of crazy somewhere. He's an obsessive, he collects pictures and articles, he profiles his marks before he kills and with as quiet as he's been since the bridge, you can bet he's planning something else."

Hmm, yes, he has a point. The laptop will tell them more. It can wait until morning.

"Aren't you going to arrest me?" he asks, bewilderment and resignation in his weary eyes, so unlike the man she woke up with not 16 hours earlier.

"Hmm," she hums casually, "nope."

"No?"

"No. You did what you had to. As far as I'm concerned, it was self-defense. He may not have attacked you today, but we both know he would have, eventually," heaving a sigh, Kate snuggles closer to him, "I'm so sorry, Castle," she whispers into his neck, "I should have believed you when you said he wasn't gone. I just thought… I wanted to think…"

"In the eyes of the law - " she cuts him off, climbing fully into his lap and winding her arms around his neck, looking deep into his baby blues – so scared and confused – searching for him in there, willing him to believe her. She's got one chance to reassure him, to keep him calm, to make certain he doesn't spiral out on her.

"The eyes of the law need glasses."

It's wrong, so very, very wrong. But the knowledge that he loves so fiercely, that he cares so deeply about his people, that he'd do this, risk it all? It lights a fire in her, kindling somewhere in her chest and spreading far beyond, settling below her navel.

"Just arrest me, Kate," Castle chokes out, trying to push her away. Not going to happen. Arms still around his neck, she tugs him downward, leverages him so that he's braced on his forearm and she's on her back, vulnerable beneath him. Forcing him to look her in the eyes. Good.

"I love you, Castle."

"Why?" voice anguished, he rants, "I've just fucked everything up. How can you- I _killed,_ Kate. Not in self-defense. It wasn't deadly force, it was murder."

She shakes her head. "Castle, you saved countless lives. Possibly your own and mine included. We both know Tyson would kill again, and again. None of our family and friends were safe with him alive."

Her mouth seals over his, swallowing any protests. She doesn't want to hear any more, but he's not responding, stunned still, too overwhelmed. The only other time he's rejected her touch was when she showed up at the loft that terrible, beautiful night, soaking wet in more ways than one and finally ready… and he wasn't. Not at first.

Oh, Castle… her heart aches for him, mind scrambles for something to say or do to bring him back.

"I just want you, Castle," she breathes, and he snaps up at the triggered memory. "I just want you."

"You're a cop…" he's giving in, grasping at anything he can to make her run. She won't. She knows that now.

"Yes. I'm glad you're aware of that," she says flatly, "you are, then, also aware that I make decisions about others' life or death, and my life or death, on a daily basis. You're aware that I've been in the position to use deadly force, you've seen me do it, in fact."

He nods, offers no resistance. That's encouraging.

"Get undressed, Castle," she requests, chuckling at his confusion. "Evidence," she explains, "we're going to dispose of them properly."

He hovers above her, unmoving. Oh for…

"For fuck's sake, Castle, you're not going to prison. We're going to dispose of the evidence properly, go through that laptop, and we're going to bring in Ryan and Espo before the body is discovered. They've kept quiet about Montgomery, they'll keep quiet about this. As far as the department is concerned, you killed Tyson once already, and they're not going to turn rat, especially not over Tyson. This… complicates things, but it doesn't change anything. Not really."

Kate gasps as he buries his face in her neck, growling out apologies, pleas, expressions of adoration and sorrow.

"Get undressed," she whispers, "then shower." _Let me in, let me in…_

"Come with me?" his little-boy-lost voice is back, sweet and still scared and thank-god he hasn't shut her out. She's won; he's hers again.

"Yes," relief flashes through her, a balm against the battery, "yes."

Castle rises and Kate sighs, wishing that he would have stayed in spite of the necessity of separation.

"I'll give you a few minutes alone. I'm going to call Ryan and Espo and tell them to meet us here in the morning. Okay?"

The writer indicates his assent with a noise and trudges off to the bathroom, shoulders sagging under the strain of the day. Clothing falls to the floor in a heap – destined, she decides, for donation. Throwing evidence away is never a good idea. Better to simply shift it onto someone else, someone with no connection to it.

The laptop will prove more troublesome. They'll see what it knows, then she'll decide how best to deal with it.

It's not something she ever envisioned herself doing, concealing evidence, but that line was crossed three years ago with Montgomery, and Montgomery – good things he did and all – deserved that loyalty far less than Castle.

If she's honest with herself (a frighteningly irregular occurrence in the past few months), she knows there's very little he could do to break her faith in him now, almost nothing at all that could make her stop loving him.

The thought should scare her.

Instead, it just excites her.

* * *

Later, they lay on her bed, flickering light and shadow from the parties in the streets below playing hopscotch on the walls, Castle on his back beneath her as she tenderly examines his bruised body. He winces as the liniment-soaked cloth she holds touches a new spot, bright red while others are already turning blue. Skin cooling instantly with the evaporation of the alcohol, he sighs in relief and stares up at her placidly, trusting.

"I wrote about it, you know," he admits quietly. "I fantasized about it."

"Killing Tyson?" he winces again.

"Yeah. I… I don't know how you stood it, with Bracken. He didn't even kill anyone I love, hadn't yet succeeded anyway, and I couldn't let it go. I couldn't stop."

Truth time, Kate.

"I didn't." The confession slips from her.

"Didn't what?"

Oh, do they have to do this here? Now? While they're both nude and he's still reeling from his own torment and while he needs her to be strong, not completely fucked up?

Obviously they do. A trembling hand closes around her arm, insistent but composed. There's no getting out of it now.

"I didn't trip, when the car blew up. I knew ahead of time and I weighed my options and I was going to save him, but I changed my mind at the last second. Made myself fall so that I didn't have to save him." It all tumbles out in a barely-audible wreck and she's not sure he heard any of it until he exhales in stunned incomprehension.

He doesn't look revolted. That's a good sign.

It's not quite an invitation to continue, but she's been holding it in so long, and she's so tired, and he should have known from the start but the longer she hid the truth, the harder it became to face, when he was so good and innocent and she was irredeemable. And now it's out there. And she loves him, and she accepts what he did – a shivering, shadowy part of her loves it, in fact - and maybe he won't reject her in return.

"The chance of him getting off on some technicality, waiting for him to come for me – for us – to stop us from investigating, watching him drag Montgomery's memory through the mud if he got caught… I couldn't take it, Castle. I just decided it was – if you ever tell anyone I said this, I'll shoot you in the foot – a sign from the universe. And I let him die."

Castle is quiet and she won't look him in the eyes and see the end if that's what's coming.

"Good."

Her head snaps from its shameful bow to find him sitting up, defiance and fire roaring in him.

"Good?"

"Good. He deserved it," Castle states coldly, simply. "Your mother's death took so many years from you, Kate. _He_ tried to take you away. It's not like you ordered the bomb built. It was just there, and taking advantage of it was your good fortune."

She hardly knows what to do with this side of her partner, best friend, lover, fiancé. She once dismissed it. The time he went apeshit on a suspect who threatened her – he was just defending his partner. Beating up Lockwood's henchmen when they were holding Ryan and Espo – desperate times. The time he tortured a guy for information – a father's love. The little flashes spread out here and there over the years had been so easy to ignore, to excuse away, to chase the shadow back underneath him like the noontime sun.

It's not so easy to ignore now.

Once again it occurs to her that this should scare her, but… it's Castle. He's always had this side to him, she reasons – he's always been capable of just about anything, when it comes to his loved ones.

It makes her love him more. More sure of him.

"I love you," she can't say anything else, so she whispers it over and over until her hair's streaked with his tears and his neck collects her own.

"I'm so sorry I didn't tell you. I thought you'd…" he shuts her up, crashing his lips to hers, fierce and hungry and sorry and _please _and _yes._

It's incongruous. It's so good-bad-right-wrong, so _them_ that it breaks something in her. The apprehension, the remnant distrust, the fear that he'd find something ugly in her own shadow and leave. They corrode and dissolve away, burn up in the fire as something stronger forges between them.

He's stroking her hair like she's the most precious, fragile thing he's ever seen. The evidence of his arousal pressing against her thigh is contradictory in the best way, and she whimpers at the dueling sensations, the ambivalence, the love and the darkness both making her need him more.

It's depraved. She doesn't care.

"Tell me what it was like," she moans as his hips buck involuntarily, pushing his tip against her slick folds, half-ashamed of her body's reaction to this_,_ but wanting it none-the-less.

"I… Kate?" Permission passes to him from her lips as she leans down, coming chest to chest with him, her breasts brushing his naked skin and making them both shiver.

"Terrible," he exclaims into her mouth at last, caught between wanting to say what he thinks she wants to hear, and wanting to tell the truth. "And good."

She rocks above him, encouraging him to keep talking. Unable to stop, unable to take it further just yet, she grinds against him in suspended animation, traitorous wetness seeping from her and she knows he feels it.

"It was like I wasn't even all there. Part of me shut down. I… I forced myself not to think of him as a human. And he barely is. Was. But… I never want to feel like that again. I didn't think he was human, but I wasn't either. Not while it was happening. It started out as being so angry that he invaded our privacy, that he threatened you, that he tried to have Ryan framed, so happy that it was going to be over… but when I was on the floor with my hands around his neck, it wasn't even about that. I just wanted to see him die. I needed to see him die, to know he was dead so that we could..."

"That we could what, Castle?" she prompts. She wants to hear it. Needs to hear it.

"That we could really have forever," Castle responds, hushed and reverent and scared out of his mind. "That we could get married and be a family and… if you want… we could have a family of our own, without worrying about him watching, or waiting for him to strike, or planning things based around the possibility of Jerry-fucking-Tyson showing up to wreck it all."

She whimpers, wetness coating her thighs at his words.

"God Castle, I want that so much," she cries, hopelessly turned on, "we can have that now. No more Tyson. No more Bracken."

"We can," he sighs, finally giving in to the relief and safety of her embrace, her acceptance, her eagerness to share this forbidden fire with him. "We can."

Suddenly she's unseated from her perch atop him, sitting on the bed while he rummages through her nightstand. Producing two plain black silk ties, he hands them to her, watching her reaction guardedly.

They don't do this often. He's perfectly content to defer to her (mostly) at work – she is the detective, after all – but at home, he's anything but passive or meek. Especially in bed. His more feral nature comes out in spades there, and often remains barely contained for days after some of their more adventurous nights. He knows her need to let go, to let someone else take charge. He knew it before she did.

So it's a surprise that tonight, of all nights, he's asking her for this.

Excitement chasing down the lingering nervousness, she goes to bind one wrist to each side of the bed, until dark inspiration strikes.

She watches him carefully as she secures both hands above his head, binding them together. That seems okay.

It's when she slips the second tie around his neck that he tenses.

"What are you doing?" he squirms under her, voice hoarse like he can't quite remember how to operate his oft-overused larynx, eyes betraying barely-contained panic, but underneath that, a spark. She knows he's into it. Almost. "Kate, that's- I don't-"

"It's what?" she applies pressure to the tie. Not enough to make breathing difficult. Just enough to let him know it's there.

"This is wrong…"

"Oh, very," she purrs. "But you like it."

No, he protests.

But he doesn't give her his safeword. She reads the text between the subtext, knows him enough to trust that anything that's not a safeword is implicit permission.

Sinking down on him without warning, she relishes the way his blunt tip spreads her, hurts just a little, hurts so good. It always does.

"Yes."

She rewards him, rising up and grinding back down on him, angle just right to hit her front wall, drawing a gasp from her and a shudder of pleasure from him. He's blinking placidly up at her, playing the role indulgently, letting her have her fun even though they both know he could escape his restraints and turn the tables so very quickly. That thought sends a shiver of pleasure down her spine. She loves it when he does.

Sucking his pulse point, she feels his heart beating rapidly, tightens the tie just a little.

"God, Kate," he groans, thrusting up into her and striking her in just the right spot. Fuck. "I love you, I love you," he chants, "I'm so sorry. I love you," he's babbling, apologies and affirmations.

Skin gliding against slick skin, they rock back and forth. Gently, at first; testing and re-establishing and re-learning each other in the new light in light of the dark.

But soon enough Castle slips his hands from their binds and the night begins in earnest.

She's left her nails long and covers his bruises with scrapes, and he leaves the phantom tracks of his strong teeth across her body as a trickster in the snow, uncaring of where they are and how long she'll need to wear turtlenecks to cover them.

Screaming, pinning, pulling, grabbing, pushing, battling with each other until the parties in the streets and buildings fall to mute, and they're both left aching and naked. Still unsatisfied, barreling through the directionless nighttime with no end in sight. Above, below, forward, behind. They surround. Unable to stop, they're left hours later still needing each other with a ferocity that neither anticipated. High off the shared secrets, the love, the sinful side of each other – she can't get enough.

Their shadows step out from underneath their flesh, at last ready to play, to act, to dance, to know and mate each other as thoroughly as their daylight counterparts.

As he pounds into her, hissing in her ear as he hovers above her and grips her hips so hard that they bruise, the cool and smoky air of first light filters through her cracked window, cleansing the still from their room and carrying her cries and his growls out with it.

* * *

He wakes her some time later. She doesn't remember when he tied her to the bed, only what he did to her after. The memory brings a catlike smile to her face as she stretches as far as the binds allow, before he releases her and they rise to make coffee and cover the shadow-kisses, red and blue and turning black, before Ryan and Esposito arrive.

The tie remains around his neck, angry friction marks forming underneath it.

* * *

_Complete. For now. When Kink Meme is over, I may continue this into a larger story, but for now, it stands as is. Sorry, no neat wrap-ups or easy answers. Just them._

_I'd love to know what you thought. Comments, questions, concerns, complaints and constructive criticisms are all welcomed and appreciated._


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